parasitic entity born out of Xavier's cells who manifests telepathy, psychokinesis, hyper-regenerative powers, intangibility, psi-plasmic armor, heat bursts, and the ability to analyze genetic codes then absorb them into "her" body

Notes:

Ernst and Cassandra Nova were addressed as one being in the future timeline Here Comes Tomorrow. However, Ernst and Cassandra Nova have been depicted as separate and distinct in the pages of New X-Men and Astonishing X-Men.